"Star Wars: The Last Jedi" will be in theaters on Dec. 15, 2017

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Luke Skywalker (Mark Hamill) has been missing in action for quite a while, and in "Star Wars The Last Jedi", moviegoers will finally figure out why--and what he's been up to since his mysterious disappearance.

A behind-the-scenes video featuring new footage from the blockbuster, including scenes with late actress Carrie Fisher's Princess Leia and a slew of new aliens, was shown as part of Disney's D23 Expo in Anaheim, California, Saturday, following the first trailer's April debut.

Kathleen Kennedy and Ram Bergman produced the movie, which Rian Johnson directed.

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Hamill, who was made a Disney Legend Friday, has kept his character's whereabouts a secret.

"I might be one of the most valuable characters to Lucasfilm--not because I'm a legacy character, but thanks to short term memory loss, I don't remember what I had for breakfast," he said at the Star Wars Celebration in April in Orlando. "I'm joking, but even when I went in and did ADR and saw this footage, it was like an out of body experience. It's so contained in its own world."

After "The Last Jedi", "Star Wars: Episode IX", the final installment of the current trilogy, is slated for release on May 24, 2019. Director Colin Trevorrow is writing the script with Derek Connolly.